Attenuated Total Reflection-Infrared Nanofluidic Chip with 71 nL Detection Volume for in Situ Spectroscopic Analysis of Chemical Reaction Intermediates

Engin Karabudak, Barbara Mojet, Stefan Schlautmann, Guido Mul, Johannes G.E. Gardeniers

Research output: Contribution to journalArticleAcademicpeer-review

20 Citations (Scopus)

Abstract

We present a micromachined silicon attenuated total reflection-infrared (ATR-IR) crystal with integrated nanofluidic glass channels which enables infrared spectroscopic studies with only 71 nL sample volume. Because of the short path length through silicon, the system allows IR spectroscopy down to 1200 cm–1, which covers the typical fingerprint region of most organic compounds. To demonstrate proof-of-principle, the chip was used to study a Knoevenagel condensation reaction between malononitrile and p-anisaldehyde catalyzed by different concentrations of 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) in solvent acetonitrile. By in situ measurement, it was demonstrated for the first time that at certain concentrations of DBU, reaction intermediates become stabilized, an effect that slows down or even stops the reaction. This is thought to be caused by increased ionic character of the solvent, in which protonated DBU stabilizes the intermediates. This clearly demonstrates that infrared mechanistic studies of chemical reactions are feasible in volumes as little as 71 nL.
Original languageEnglish
Pages (from-to)3132-3137
Number of pages6
JournalAnalytical chemistry
Volume84
Issue number7
DOIs
Publication statusPublished - 2012

Keywords

  • METIS-285189
  • Physical chemistryProduktie- en procestechnieken
  • IR-82065

Fingerprint Dive into the research topics of 'Attenuated Total Reflection-Infrared Nanofluidic Chip with 71 nL Detection Volume for in Situ Spectroscopic Analysis of Chemical Reaction Intermediates'. Together they form a unique fingerprint.

  • Cite this